Three-Dimensional Finite Difference Modeling of Surface Wave Propagation Across the Barents Shelf

• Main Authors: McLaughlin, K. L., Barker, T G., Stevens, J. L., Shkoller, B., Day, S. M.
• Other Authors: S-CUBED LA JOLLA CA
• Format: Text
• Language: English
• Published: 1991
• Subjects: Physical and Dynamic Oceanography; Geology; Geochemistry and Mineralogy; Seismology; Nuclear Explosions and Devices(non-military); *WAVE PROPAGATION; *TECTONICS; *UNDERWATER EXPLOSIONS; *SURFACE WAVES; *OCEAN BOTTOM; *SEISMIC WAVES; MODELS; EXPLOSIONS; FAR FIELD; DEPTH; EXPLOSION EFFECTS; REGIONS; SURFACES; BOUNDARIES; THREE DIMENSIONAL; CONTINENTAL SHELVES; PATTERNS; FOCUSING; BANDWIDTH; AMPLITUDE; SEISMIC VELOCITY; SEDIMENTATION; RAYLEIGH WAVES; LOVE WAVES; SCATTERING; DENSITY; SIMULATION; FREQUENCY; SEISMOGRAPHS; VELOCITY; CONVERSION; BARENTS SHELF; SEISMOGRAMS; NOVAYA ZEMLYA; MULTIPATHS; Novaya Zemlya
• Online Access: http://www.dtic.mil/docs/citations/ADA249865; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA249865

A three-dimensional (3D) finite difference simulation has been conducted of surface waves propagating across a laterally heterogeneous velocity and density model of the Barents Shelf. The 3D model encompasses a region of 1620 by 810 km to a depth of 210 km. The calculations were designed to model 0. 02 to 0.05 Hz surface waves from an isotropic source at Novaya Zemlya in a 3D heterogeneous model. Extensive focusing/defocusing of surface waves are observed for the entire bandwidth from 0.02 to 0.05 Hz. Focusing/defocusing is observed to frequency dependent such that the amplitude patterns of 0.02 and 0.05 Hz are not correlated. A hybrid Fresnel-Kirchoff technique is used to project Rayleigh wave amplitudes to teleseismic distances. About 25 percent of the variance of the far-field Rayleigh wave amplitude scatter from Novaya Zemlya events can be explained by near-source (within 800 km) scattering. Multipathing was observed to occur for 0.04 to 0.05 Hz Rayleigh waves, consistent with observations of Novaya Zemlya events observed at the Norwegian Seismic Array (NORSAR). Rayleigh- to-Love conversion is observed in the simulation in localized regions along structural boundaries. Such scattered Love waves should be observable at narrow azimuthal ranges. Surface Waves Explosion Seismology, Finite Difference Novaya Zemlya, Barents Shelf.